Manufacture of cores for foundry work



EMIL KLEINSCHMIDT, OF FRANKFOBT-ON-THE-MAIN, AND CARL FOHR, OF MIESBACH, OBERBAYERN, GERMANY.

MANUFACTURE OF CORES FOR FOUNDRY WORK.

No Drawing.

To all whom it may concern Be it known that We, EMIL KLEINSCHMIDT, a citizen of Germany, residin at H nspergstreet 7, Frankfort-on-theain, ermany, and CARL FoHR, a citizen of Germany, residing at Miesbach, Oberbayern, Germany, have invented certain new and useful Improvements in the Manufacture of Cores for Foundry Work (for which We filed applications in Germany, Dec. 18, 1916, and March 31, 1919; Austria, May 2, 1919; Hungary, May 22, 1919; Czechoslovakia,July21, 1919; Switzerland, May 15, 1919; Denmark, June 1919; Sweden, May 24:, 1919; Norway, June 11, 1919; Netherlands, May 23, 1919), of which the following is a specification.

In making moulds for metal castings there are used as binding agents for the cores preferably such substances .as thick oils, viscid vegetable syrup, viscid molasses and the like. All these core binding media have the disadvantage that, owing to their viscosity, they admix with the cores and only with much difiiculty, so that a comparatively large quantity of these expensive binding media is necessary."

According to this invention cores for foundry work are produced in such a manner that convenient binding substances atomized by suitable atomizers, e. g. scat tering nozzles or Wind sifters are incorporated in the core material (sand). As con venient binding agents pitch, asphalt or other bituminous substances and resins are used.

This invention is realized for example in such a manner that pitch is brought by means of scattering nozzles or wind sifters into a finely atomized form or into the form of substantially impalpable powder. Part of this powder, e. g. 2 to 3% is admixed with the core sand as binding agent, whereupon the desired-cores are made from the mixture in the usual manner by mouldin% and drying.

esides the advantage already mentioned, viz, the considerable economy in expensive binding agents, special advantages are further obtained in so far as the pulverized pitch melts easily in the kiln and consequently produces a great binding eflect, imparting considerable resistance to the core. At the casting the fine pitch powder is completely burnt out of the cores where- Serial No. 497,019.

by the cores acquire the desired porosity so that the gases can escape easily from the mould.

The pitch which has been finely pulverized in accordance with this invention, does not cake together under normal conditions but remains in the fine amorphous state. It is consequently very handy and it can further be supplied to the foundries directly in the form of fine powder packed in sheet metal drums.

It has been found out further that even considerably smaller quantities of the expensive binding agents, such as pitch, asphalt, resin and the like will be suflicient for the production of cores of sufiicient durability if other cheaper binding agents, e. g. inorganic binding agents, dust of brown-coal, peat or lignite or similar substances are added to the pitch, asphalt, resin or the like which have been pulverized according to this invention.

Loam, clay, red clay, kaolin, schistous clay, pozzuolana cement, Portland cement, magnesia cement, lime, gypsum, alkalies, blast furnace dust and the like have proved to be convenient additions.

By the addition of such binding agents the further advantage is obtained that the caking together of the finely pulverized pitch, asphalt or the like when stored is avoided even at higher than normal temperatures.

It is not possible to produce a sufficiently fine powder when pitch, asphalt or the like are disintegrated by means of the usual crushing devices such as crushers or disintegrators. The advantages realized according to the present invention cannot be obtained by the use of such products from disintegration. In order to ensure a good binding of the core mass considerably larger quantities of such products from crushing or disintegration would have to be used.

The mechanical disintegratingprocesses have further the inconvenience that the disintegration is to be carried through only with difiiculty owing to the continuous clogging of the mills, the pulverized product being so sticky that it cannot be stored or transported as the particles would cake up at once.

We claim 1. Core material for foundry work containing in intimately mixed condition a distributed therein a binding agent in the 10 binding agent comminuted to a substantially form of a substantially impalpable powder.

inpalpable powder. In testimony whereof we hereunto aflix 2. Core material for foundry work conour signatures. 5 taining in intimately mixed condition inor- Signed at Frankfort-on-the-Main by ganic binding material and an organic bind- EMIL KLEINSCHMIDT mg material reduced to substantially lmpalpable powder I Melsbach, August 5, 1921.

3. A core for foundry work containing CARL FOHR. 

